Pneumatic fittings are parts used to connect sections of pipe, tube, and hose in pneumatic (pressurized gas) systems. Compared to hydraulic fittings, pneumatic fittings are typically characterized by tighter seals and lower pressure requirements. They are frequently used in pneumatic logic control systems and instrumentation.
Types of Fittings
Pneumatic fittings are distinguished based on the connection type and function it performs.
Pneumatic fittings are attached via a number of different connection methods, each with its own conveniences and advantages.
Once the type of fitting required has been determined, the most fundamental aspect of pneumatic fittings can be addressed: proper sizing. Proper sizing is essential to successful fitting selection, as oversized or undersized parts will either be completely incompatible or will seal or connect inadequately. The two systems of measurement are Metric (mm) and English ("). The first step to proper sizing is selecting the appropriate measurement system for compatibility with the equipment or assembly being fitted. The sizing of a pneumatic fitting is defined by the size of vessels it connects to. Tubes, hoses, and pipes are sized based on inside diameter (ID) and outside diameter (OD), measured in inches (in) or millimeters (mm). A fitting designed to connect to a tube with a 2" OD is rated as a 2" OD fitting. Inside diameter measures the diameter of the empty portion of the cylinder, while outside diameter includes the thickness of the tubing wall.
Pneumatic fittings often are rated for certain temperature and pressure ranges based on what they are designed to handle. Operating pressure range is the working range of pressures or the pressure ratings at which the fitting was designed to operate, typically measured in pounds per square inch (psi). Operating above or below this rating could cause the fitting to fail (i.e. break, leak, lose its seal). Operating temperature range is the working range of temperatures or the temperature ratings at which the fitting was designed to operate, measured in degrees Fahrenheit (°F) or degrees Celsius (°C). Operating above or below this rating could cause the fitting to fail